Hello All,

I have a 4k video which I imported to Kdenlive. But I cannot drag into to timeline. If I drag, only the audio is active. I tried to select video, but its not allowing me to select. Only audio channels can be selected.

Attached is the screenshot and also you can see my video clip details
https://i.imgur.com/C4uVXvZ.png

I believe I have fixed the problem on my PC, but before you start reading, please see this note.

NOTE: When using that same stock PPA Stable Version with 16 threads specified, everything seems to work perfectly and the CPU is running at 80% usage! YAY!
The stock PPA Version I'm using is called 4:20.08.2-2 in Synaptic Package Manager and 20.08.2 in the KDENLIVE about section. Specifying 32 threads wrecks it, but it didn't seem to in the beginning. I also had to change the style to Breeze and the Color Theme to Breeze High Contrast in order to be able to see text on the screen.


I have had the very same problem with the newest versions of KDENLIVE in Ubuntu 20.04 LTS, but I have it working now, although I don't know why or how.
Full HD projects seem to work fine, and I was able to drag 4K UHD video clips into full HD projects, but that might have been after the problem was fixed.
I could and can encode the 4K UHD video clips into full HD as well, but they fill up my drive M.2 storage fast.

Also the interface was all messed up, at least the color pallet. The background was gray, and the text was also gray, and when I selected it, it was a little darker so I could see it. It didn't matter what style or color setting I picked.

I can now drag 4K UHD Video clips into my timeline and render them.

The first thing I did was get the appimage versions and latest test builds, after installing the stable ppa repo and installing that as well.
I tried using the daily builds and stable builds, but it didn't seem to be working. kdenlive-20.11.70-3986e1b-x86_64.appimage
kdenlive-20.08.2-x86_64.appimage

Then I got the older appimage I had saved kdenlive-18.08.3-x86_64.AppImage and ran that one, and it was a little strange because it seemed to use the new interface. I'm used to the KDENLIVE from the repositories in Ubuntu 18.04 LTS and I like that interface better.

Now when I drag 4K UHD Videos into the timeline, I have to zoom out of the timeline a bit, and drag the 4K UHD Video around to the right, until it enters the project, and it also seems to depend on the line. I have 7 video tracks and 2 audio tracks in my project. Unlike the older version I prefer, the new version puts the audio track in an audio track, and the video track in a video track. In order to get them next to each other, I have had to ungroup them, move them closer together, and use SHift to re group them again, however I use a seperate audio track that has been edited, so I remove the audio track anyway most of the time.

When I open KDENLIVE from my system menu, it no longer displays a version under about. It seems to be running the appimage version, as if it installed itself instead. It still seems harder to drag 4K UHD videos to the timeline however, than if I just run the Appimage version from the appimage file I downloaded. kdenlive-20.11.70-3986e1b-x86_64.appimage OR
kdenlive-20.08.2-x86_64.appimage

I have learned that when KDENLIVE starts acting very strange, the best thing to do seems to be to delete the kdenlive files in /home/user/.config
And try to re-open the project, but I usually also have to delete the project file as well, as it also seems to screw up KDENLIVE once corrupted in some way. Probably a project config file.
Then if that doesn't work, you can try uninstalling KDENLIVE, deleting the kdenlive files in .config, and also deleting your project files (but not the original video and audio files), and start over again. This can clear up everything.

Of course you also need the right codecs installed. I use JULinux 20.04.6 RC1 right now http://www.JustUseLinux.COM and it's finish install program automatically installs most or all of the codecs you need, but I still had to go through the above steps and appimages in order to get it working.

In addition (don't know if this is relevant) I installed OpenShot Video Editor from synaptic package manager, blender was already installed, and I also tried the appimage version of OpenShot video editor and it asked me if I wanted to install it and I did. OpenShot-v2.5.1-x86_64.AppImage It was after this that KDENLIVE allowed me to drag the 4K UHD videos to the timeline.

OpenShot's parallel rendering doesn't seem to be working right, because I can see individual CPU threads taking turns on the rendering, and it's slower than KDENLIVE.

I'm using an AMD Ryzen 9 3950X Processor 3.5GHz 16-Core 100-100000051WOF 32-Thread CPU to render my videos. I don't seem to have a fancy GPU that can outperform my CPU for video encoding / rendering. It looks like KDENLIVE lists GPU rendering as an option now, but it has a red X next to it. I'm not sure what the best workstation GPU's are for rendering.

the blender plugin in OpenShot uses my GPU to render 3D things, but it seems to be a single core CPU process, and the CPU gets incredibly hot, even though it's only using one thread to do the job, and it bounces that job around to different threads. The heat doesn't seem to be evenly distributed on the CPU very well.

I hope that solves your problem, and helps others. I hope to make a video very soon.

My next thing to tackle, is getting LEVELATOR to run on wine again in JULinux 20.04, as it ran well in 18.04 before. I was able to replace levelator by using a compressor in Audacity. Thanks so much for your question, I hope my response helps everyone, and may Jesus bless you, your family, your income, and all that God has for you to do!